Why do we do it, that is use acronyms or words that can only be understood by the 'in crowd'? Is it because we are worried about using up too many words or because we just get into a habit of saying them. That's the thing when we become the member of a club or join an organisation, it doesn't take too long before we start using the language used by that group.
Now here is a real problem, what if the group wants to have an open door policy, yet the language used is very much the opposite, it closes doors and turns the group into something that is exclusive. Wannabe members may get the wrong message and think it's not for them because they do not understand the 'lingo' as it were.
As Christians, we are not immune to this situation, words like justification, sin, fellowship, redeemed, and acronyms like CCM, (Contemporary Christian Music) WWJD (What Would Jesus Do) , ACTS (Adoration, Contrition, Thanksgiving, Supplication) are used in churches everyday, and can be difficult to understand (even for the regulars) and be a barrier to people who want to engage with church. Maybe we just need to explain what we mean? 1 Corinthians 14:9 (CEV) leaves us with a challenging thought, "That’s how it is when you speak unknown languages. If no one can understand what you are talking about, you will only be talking to the wind.".